I can't believe I haven't seen this thread.
Avowed, I have the same exact engine, new never run. I am having the EXACT trouble you are and I have done everything and I mean everything to get it going. I get so mad pedaling all over the place and almost having heart attacks from pedaling.
Mine has the exact symptoms as yours, wet plug, has spark, "kinda" sputters and head gets only warm, but the engine just will not kick in and GO!.
Using the throttle has no effect at all or the choke. It does nothing and is quite frustrating.
I'm going to check the MAG resistance tomorrow and probably order an entire new MAG and CDI to try....
If that doesn't do it then I give up..... I have no idea what it could be.....I feel your pain.